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Freedom of Information data reveals poor monitoring of the carcinogen formaldehyde, prompting researchers to demand urgent regulatory intervention for thousands of healthcare workers
Airborne concentrations of formaldehyde routinely exceed European safety limits in 70 per cent of UK pathology labs.
A regulatory gap in NHS workplace safety
Formaldehyde is a heavily used human tissue preservative, but it is also a known human carcinogen linked to nose and throat cancers, leukaemia, respiratory issues, and reproductive health risks.
Emerging medical evidence additionally connects long-term exposure to cognitive impairment and motor neuron disease. Because of these severe risks, the United States Environmental Protection Agency declared in 2024 that the chemical presents an unreasonable risk of injury to human health.
In 2021, the European Union updated its binding workplace exposure safety standards, cutting the long-term eight-hour average limit down to 0.3 parts per million. Because the United Kingdom exited the European Union in 2020, it chose not to adopt these tighter protections.
Instead, the UK maintained an exposure threshold of 2.0 parts per million, which is currently the highest allowed limit in the world.
Infrequent monitoring across hospital trusts
To evaluate the actual safety of laboratory environments, a research team analysed a full 12-month period of monitoring logs spanning 2024 and 2025.
They secured Freedom of Information disclosures from all 122 National Health Service (NHS) Trusts across England, Scotland, Wales, and Northern Ireland, capturing data from 117 separate cell pathology labs managing more than 1.7 million distinct monitoring events.
The investigation, published online in Occupational and Environmental Medicine, discovered that air testing was remarkably rare despite labs processing an average annual caseload of nearly 37,000 surgical tissue specimens.
Nearly three out of four laboratory sites measured airborne concentrations only once a week or less. Within that group, 15 per cent tested air quality quarterly, and 4 per cent performed safety checks just once a year.
Failure to control airborne concentrations
The collected records proved that air contamination is poorly managed. At 70 per cent of the monitored laboratory sites, airborne formaldehyde regularly climbed past the European Union safety threshold.
Only 11 per cent of the facilities that tested their air daily managed to keep their chemical levels consistently below that European limit.
While the labs technically remained within the relaxed UK legal boundary, nearly a third of the facilities logged an airborne concentration spike higher than 2.0 parts per million at least once during the year.
The researchers emphasised that substantial evidence confirms formaldehyde causes serious health deterioration at concentrations far lower than the official UK legal limits.
Demands for national intervention
An accompanying commentary written by occupational health experts from Utrecht University and the University of Manchester noted some structural data gaps, pointing out that the logs lacked specific details regarding whether samples were taken from stationary room monitors or personal wearable badges. Even with those limitations, the experts concluded that NHS laboratories are clearly failing to reduce exposures to the lowest levels reasonably practicable under current UK hazardous substance regulations.
Because the NHS currently lacks universal guidelines or standards to regulate this chemical, researchers are calling for immediate external oversight by the Health and Safety Executive.
Protecting the 28,000 laboratory staff working in England alone will require structural infrastructure upgrades, improved personal protective equipment, mandatory employee safety education, and updating UK chemical exposure limits to match modern European safety standards.